Thermostatic magnet-protector.



No- 826,910. PAIBNTED JULY 24, 1906.

J. THULIN.

THERMOSTATI U MAGNET PR0TEOT0R. v ABPLIOATION FILED mm. 12, 1904.

tical section on the line 22 of Fig. 1.

JOHN T'HULIN, OF CHICAGO, ILLINOIS.

TH E'R M OSTATIC MAG NE T-PROTE'CTOR Specification of Letters Patent.

Patented Ju1y24, 1906.

Application filed December 12,1904. Serial No. 236.60%

To all whom it may concern.-

Be it known that I, JOHN THULIN, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in ThermostaticMagnet-Protectors; and Ido hereby declare the following to be a full,clear,.and exact description of the invention, such as will enableothers skilled in the art to which it appertains to makeand use thesame.

My invention relates to a novel construc tion .in a thermostatic devicefor protecting the coils of electromagnets against burning out, theobject being to provide a device disposed in the circuit of the magnetfor shortcircuiting the latter when the coil of such magnet attains ahigh temperature and before the same burns; and it consists in thefeatures of construction and combinations of parts hereinafter fullydescribed and claimed.

In the accompanying drawings, illustrating my invention, Figure 1 isacentral longitudinal section of my device disposed in proper relativeposition on the coil of an electromagnet and in the circuit of same.Fig. 2 is a ver- Fig. 3 is a section similar to Fig. 1, showing amodified form of construction. Fig. dis a detail fragmentary plan viewof the modified form of construction shown in Fig. 3. Fig. 5 is a sideelevation of a block of fusible metal employed.

My said device comprehends the use of a spring or spring-actuatedcircuit-closer which is disposed in the circuit on one side and is held.to maintain the circuit closed through said magnet by means of a blockof low-fusible metal which is adapted to be molten by radiated heat fromthe coil to release said circuit-closer, and thus short-circuit themagnet before the same can burn out.

My said device comprises a flat strip A of metal preferably of a naturewhich is an excel lent conductor of heat as well as electricity, such ascopper. The said strip A is provided at its ends with flanges B and C,on which binding-postsD andE are'mounted, said postD being insulatedfrom said flange E by interposing suitable insulating material F in awell-known manner. The binding-post E contacts with the flange C on oneside of the latter and secures in place on the other side thereof ablock G, of fiber or similar stifl insulating material,

in the free end of which is a binding-post H,

which is entirely insulated from said strip A and said flanges.

Secured at one .end between a part of the binding-post D and insulationFlis a circuitcloser J, preferably consisting of suitable spring-wire,which is coiled between .its ends,

, as at K, to render it moreelastic, the freeend of said lever beingsecured to saidstrip A between the flanges thereof and adjacent theflange O by means of soft solder or similar low-fusible metal, as at L.

One of the line-wires M is connected with the coil N of the magnetthrough the bindingpost D, circuit-closer J, plate A, and bindingpost E,and as saidcircuit-closer J is disposed directly in the circuit, but byreason of its requisite elasticity it .must necessarily be made ofrelatively thin wire, .and in the event that current of large volume isemployed such circuit-closer may become heated and be thus released whenno occasion .for release arises, .and hence one or more soft-copperwires O may be interposed between the said binding-post D and the freeend of said circuit-closer J to carry the current. The said binding-postH is connected with the other linewire P, and by means ofsaidbinding-post there is secured .to' said block G of fiber in the pathof the free end of said circuit-closer J a contact-piece Q, throughwhich the circuit is closed through the line-wires M and P and opened toshort-circuit said magnet when said circuit-closer J is released. Thesaid strip Ais preferably provided with flanges R on its side edges andis relatively thin, so that when mounted on the coil of the magnet andin close contact therewith the heat .from the coil will in the event ofits becoming overheated readily penetrate to and melt said soft solderL, and thus release said circuitcloser J to short-circuit .saidcoilbefore :the same shall haveattaineda temperature su'fliciently high toburn out.

In the construction'shown in Figs. v1.and.2 the free end of thecircuit-closerJ is virtually soldered to the plate A, and hence requiresthe employment of a suitable low-fusible solder and is otherwisedisadvantageous by reason of the fact that in order to returnthecircuitcloser J to its normal positionsoldering-tools are required, and.as such magnets are contained in the casings ofarc-lampsand similarspaces it renders the work of returning such circuit closer diflicult. Ihave therefore provided the means shown in Figs. 3, 4, and 5 forobviating this difficulty. In Fi 3 it will be noted that the plate A isprovi ed with a U-shaped bend S, interposed between the flanges andproviding a recess in the lower face of the plate A. Alongitudinal slotT in said plate A extends through said U-shaped bend S and for a shortdistance on each side thereof, the said slot being adapted to receivethe free end of said cireuit-closer J, which is held therein by means ofa key U, adaptedito fit said recess and which is provided in its lowerface with a groove V to receive said circuit-closer, which thereby holdssaid key against displacement.

It will .be obvious that when said key is fused the said circuit-closerwill be released, and to return the same it is only necessary to replacethe key, as will be obvious.

My said device is particularly adapted for electric-lighting systems,particularly for arelamps to prevent burning out of the electromagnetscontrolling the carbons.

For such systems in which the lamps are connected in series my device isparticularly valuable, inasmuch as it will short-circuit one or morelamps of the series without opening the entire circuit and putting outall the lamps by reason of the burning out of'one of same.

Unless disposed in a series of circuits, as above described, thebinding-post H will obviously not be connected with either of theline-wires, and in that case the device will serve only as acircuit-opener in substantially the same manner as the ordinaryfuse-plug.

I claim as my invention 1. A device of the kind specified comprising amagnetcoil directly connected at one end to one side of the line, ametal plate disposed in surface contact with said magnetcoil andelectrically connected therewith, a spring-actuated circuit-closercarried by and insulated from said plate and connected with the otherside of the line, abody of low-fusible metal disposed on said plate andengaging the free end of said circuit-closer to maintain the same at onelimit of its movement and normally maintain the circuit through saidcoil closed, an insulating-block carried by said plate, and aterminalmounted on said insulat ing-block in the path of saidcircuit-closer, said terminal being connected with said firstnamed sideof said line and adapted, when said metal is fused and saidcircuit-closer released, to short-circuit said magnetcoil.

2. A device of the kind specified, comprising a magnetcoil directlyconnected at one end with one side of the line, a metal plate disposedin surface contact with 's aid magnetcoil and electrically connectedtherewith at its other end, a spring-actuated circuit-closer connectedat one end with the other side of the line and insulated from saidplate, a body of low-fusible metal disposed on said plate and adapted toengage and hold the free end of said circuit-closer against the actionof its actuating-spring to maintain the circuit through said coilnormally closed, and a terminal con nected with said first-named side ofthe line out of conductive relation to said plate, and in the path ofthe free end of said circuit-closer to short-circuit said magnetcoilwhen said metal is fused.

3. A device of the kind specified, comprising a magnetcoil, a U-shapedmetal plate disposed in surface contact therewith, a spring-actuatedcircuit-closer disposed out of conductive relation to said plate andcarried by one arm thereof, a body of low-fusible metal disposed on saidplate and engaging the free end of said circuit-closer to normally holdthe same against the action of its actuatingspring and in conductiverelation to said plate, said magnet-coil being disposed in an electriccircuit normally closed on one side through said circuit-closer and saidplate and directly connected at the other side with the source ofenergy, a body of insulating material disposed on the other arm of saidplate, a terminal mounted on said insulating-body and connected with thelast-named side of the line and disposed in the path of the free end ofsaid circuit-closer and adapted when said circuitcloper is released toshort-circuit said magnet- CO1 4. A device of the kind specified,comprising a magnetcoil, a U-shaped metal plate disposed in surfacecontact therewith, a spring-actuated circuit-closer disposed out ofconductive relation to said plate and carried by one arm thereof, a bodyof low-fusible metal disposed on said plate and engaging the free end ofsaid circuit-closer to normally hold the same against the action of itsactuatingspring. and in conductive relation to said plate, saidmagnetcoil being disposed in an electric circuit normally closed on oneside through said circuit-closer and said plate and directly connectedat the other side with the source of ener y, a body of insulatingmaterial disposed on t e other arm of said plate, a terminal mounted onsaid insulating-body and con nected with the last-named side of the lineand disposed in the path of the free end of said circuit-closer andadapted, when said circuit-closer is released, to short-circuit saidmagnet-coil, and a bridge piece of metal carried by said circuit-closerto increase its conductive power.

In testimony whereof I have signed my name inpresence of two subscribingwitnesses.

JOHN THULIN.

Witnesses:

RUDOLPH WM. Lorz, F. SGHLOTFELD.

